CVE-2017-2636

Condición de carrera en drivers/tty/n_hdlc.c en el kernel de Linux hasta la versión 4.10.1 permite a usuarios locales obtener privilegios o provocar una denegación de servicio (liberación doble) ajustando la línea de disciplina HDLC.

A race condition flaw was found in the N_HLDC Linux kernel driver when accessing n_hdlc.tbuf list that can lead to double free. A local, unprivileged user able to set the HDLC line discipline on the tty device could use this flaw to increase their privileges on the system.

The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix: A flaw was found in the way memory was being allocated on the stack for user space binaries. If heap and stack memory regions were adjacent to each other, an attacker could use this flaw to jump over the stack guard gap, cause controlled memory corruption on process stack or the adjacent memory region, and thus increase their privileges on the system. This is a kernel-side mitigation which increases the stack guard gap size from one page to 1 MiB to make successful exploitation of this issue more difficult.